A product number, a product name, a trademark or the like is displayed on the surface of a tablet or a capsule (hereinafter, referred to collectively as “tablet”) for identification of a product and prevention of accidental ingestion. The display on the tablet is made by engraving at tabletting or print processing such as transfer printing or inkjet printing. The inkjet printing is capable of performing printing on the tablet surface in a non-contact manner and is thus less subject to powder adhering to irregularity in the tablet surface and excellent in sanitation. Thus, in recent years, various types of inkjet type tablet printing devices are proposed. For example, in a tablet printing device disclosed in Patent Document 1, a tablet is conveyed by a conveyor belt with one surface (lower surface) of the tablet sucked and held, and predetermined print processing is performed on the other surface (upper surface) thereof by an inkjet head disposed on the conveying path.